UV absorbing container glass compositions

ABSTRACT

A container glass composition that reduces U.V. light transmission below a wavelength of about 400 nanometers, the composition having melting and forming properties similar to soda-lime-silica glass and containing SiO 2 , CaO, MgO, K 2  O, SO -   3 , and a U.V. absorbing amount of about 0.4 to 0.8 weight percent FeO+Fe 2  O 3 , and about 2 to 4 weight percent of MnO+MnO 2 .

The present invention relates to an ultraviolet light absorbing container glass composition containing SiO₂, Al₂ O₃, Na₂ O, CaO, MgO, K₂ O, SO₃ and, preferably, about 0.4 to 0.8 weight percentage of FeO+Fe₂ O₃ and about 2 to 3 weight percentage of MnO+MnO2 based on the weight of the glass composition.

BACKGROUND OF THE INVENTION

It is desirous to provide a substantially clear or a lightly tinted flint container glass composition to provide relatively clear transparent flint glass containers that absorb UV light so as to protect the liquid inside such as Champagne or wine.

As to prior art showing Fe₂ O₃ or any amount of MnO in glass composition there are the following documents:

1. Central Glass Co. U.S. Pat. No. 5,362,689.

2. Corning (Morgan) U.S. Pat. No. 5,422,755.

3. Guardian Industries U.S. Pat. No.5,214,008.

4. Ferro (Roberts) U.S. Pat. No. 4,859,637.

5. Chemical Composition of Container Glasses--Sharp (Table 1) 1930's.

Central Glass Co. U.S. Pat. No. 5,362,689 discloses a soda-lime-silica sheet glass composition that contains Fe₂ O₃ (0.1-0.60) and 5-350 ppm MnO. The MnO is used in trace amounts. The ultraviolet absorbing ingredients appear to be CeO₂, TiO₂ and SO₃. In Column 5, lines 55-66, the addition of very small amounts of MnO are discussed and there is disclosed a prohibition against the use of larger amounts of MnO.

Coming (Morgan) U.S. Pat. No. 5,422,755 discloses a soda-potassia-silica glass composition for an ophthalmic lens. There is disclosed the use of V₂ O₅ (1.5-3.5% ) and MnO₂ (1-4%). The

Guardian Industries U.S. Pat. No. 5,214,008 shows a soda-lime silica glass composition for a flat glass. CeO₂ and other UV absorbing ingredients such as TiO₂, MoO₂, V₂ O₅ and Fe₂ O₃ are disclosed, for instance, in Column 2, line 28-50.

Ferro (Roberts) U.S. Pat. No. 4,859,637 shows lead-free glass compositions with a U.V. absorbing material selected from the group consisting of cerium oxide, manganese oxide, iron oxide, cobalt oxide, copper oxide, vanadium oxide and molybdenum oxide. The glass is used with a ceramic pigment to form an ink composition.

The reprint "Chemical Composition of Commercial Glasses". (Sharp) shows in Table 1 some ancient soda-lime-silica glass compositions containing (0.54-0.9), Fe₂ O₃, and low amounts (0.61-0.97) of MnO, apparently present from contamination.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide a relatively transparent, clear flint container glass composition containing oxides of iron and oxides of manganese that absorb UV light to thereby protect liquids such as Champagne and wine from unwanted exposure to the UV light.

It is an object of the present invention to provide an ultraviolet light absorbing soda-lime-silica container glass composition consisting essentially of the following ingredients in approximately weight percents;

    ______________________________________                                                Ingredients                                                                             Weight                                                         ______________________________________                                                SiO.sub.2                                                                               69-74                                                                 Na.sub.2 O                                                                              11-15                                                                 CaO       9-13                                                                 MgO      0.5-2                                                                 K.sub.2 O                                                                               0.1-0.5                                                               SO.sub.3.sup.-                                                                          0.1-0.5                                                               Fe.sub.2 O.sub.3  + FeO                                                                 0.4-0.8                                                               MnO + MnO.sub.2                                                                         2.0-3.0                                                        ______________________________________                                    

These and the other objects will be apparent from the specification and claims that follow.

SUMMARY OF THE INVENTION

The present invention provides a soda-lime-silica container glass composition consisting essentially of the following ingredients in approximately weight percent;

    ______________________________________                                         Ingredients    Weight                                                          ______________________________________                                         SiO.sub.2      69-74                                                           Na.sub.2 O     11-15                                                           CaO             9-13                                                           MgO            0.005-3.0                                                       K.sub.2 O      0.005-1.0                                                       SO.sub.3       0.1-0.5                                                         Fe.sub.2 O.sub.3  + FeO                                                                       0.3-1.0                                                         MnO + MnO.sub.2                                                                               2.0-3.1                                                         ______________________________________                                    

The present invention also preferably provides the following:

    ______________________________________                                                Ingredients                                                                             Weight %                                                       ______________________________________                                                SiO.sub.2                                                                               69-74                                                                 Na.sub.2 O                                                                              11-15                                                                 CaO       9-13                                                                 MgO      0.5-2                                                                 K.sub.2 O                                                                               0.1-0.5                                                               SO.sub.3 0.1-0.5                                                               Fe.sub.2 O.sub.3  + FeO                                                                 0.4-0.8                                                               MnO + MnO.sub.2                                                                         2.0-3.0                                                        ______________________________________                                    

DETAILED DESCRIPTION OF THE INVENTION

The following examples illustrate the present invention.

EXAMPLE 1

A UV absorbing flint container glass composition was made by mixing raw batch ingredients including quartz, soda ash, sodium nitrate, potassium carbonate, alumina, sodium sulfate, iron oxides and manganese oxides and melting the batch to provide a container glass composition (BDB-1) containing the following ingredients, in approximate percentage by weight:

    ______________________________________                                         Percentage by weight:                                                          Ingredients    Percentage by weight:                                           ______________________________________                                         Cl.sub.2       0.0043                                                          Na.sub.2 O     13.4096                                                         K.sub.2 O      0.3412                                                          MgO            0.0053                                                          CaO            11.0386                                                         MnO + MnO.sub.2                                                                               2.0070                                                          SrO            0.0020                                                          BaO            0.0005                                                          Al.sub.2 O.sub.3                                                                              8.6059                                                          Fe.sub.2 O.sub.3 + FeO                                                                        0.4015                                                          SiO.sub.2      70.8110                                                         SO.sub.3       0.3714                                                          ______________________________________                                    

The glass was melted at 2700° F. for about 61/4 hours in a gas furnace with excess air and an oxidizable batch atmosphere. The glass can be processed like a soda-lime silica glass and it absorbs ultra violet light.

The amount of each raw batch material for Example 1 is as follows:

    ______________________________________                                         Composition - DBD-1                                                            Raw Materials     GRAMS                                                        ______________________________________                                         Quartz            354.26                                                       Soda Ash          112.81                                                       Sodium Nitrate    3.54                                                         Calcium Carbonate 96.14                                                        Magnesium Carbonate                                                                              2.50                                                         Alumina           1.91                                                         Calcium Sulphate  3.04                                                         Iron Oxides       1.97                                                         Manganese Oxides  12.32                                                        ______________________________________                                    

EXAMPLE 2

Following the procedure of Example 1, additional melts D-1, D-2, D-3, D-4, D-5 and D-6 were made according to Table 1 below.

                  TABLE 1                                                          ______________________________________                                         EVALUATION OF 0.4, 0.6 and 0.8% Fe.sub.2 O.sub.3 at 2.0 and                    3.0% MANGANESE OXIDE LEVELS                                                    MELT       MELT     MELT    MELT  MELT   MELT                                  D-1        D-2      D-3     D-4   D-5    D-6                                   ______________________________________                                         SiO.sub.2                                                                             71.05   70.85    70.65 70.05 69.85  69.65                               Na.sub.2 O                                                                            13.36   13.36    13.36 13.36 13.36  13.36                               CaO    11.00   11.00    11.00 11.00 11.00  11.00                               K.sub.2 O                                                                             0.34    0.34     0.34  0.34  0.34   0.34                                Al.sub.2 O.sub.3                                                                      1.60    1.60     1.60  1.60  1.60   1.60                                SO.sub.3                                                                              0.25    0.25     0.25  0.25  0.25   0.25                                Fe.sub.2 O.sub.3                                                                      0.40    0.60     0.80  0.40  0.60   0.80                                MnO    2.00    2.00     2.00  3.00  3.00   3.00                                NaNO.sub.3                                                                            10#/    10#/     10#/  10#/  10#/   10#/                                       1000#   1000#    1000# 1000# 1000#  1000#                                      Sand    Sand     Sand  Sand  Sand   Sand                                ______________________________________                                          COMMENTS:                                                                      1) Melt D1 uses 0.40 wt % Fe2O3 and 2.0% manganese oxide (5.64:1 molar         ratio of Mn to Fe)                                                             2) Melt D2 uses 0.60 wt % Fe2O3 and 2.0% manganese oxide (3.71:1 molar         ratio of Mn to Fe)                                                             3) Melt D3 uses 0.80 wt % Fe2O3 and 2.0% manganese oxide (2.82:1 molar         ratio of Mn to Fe)                                                             4) Melt D4 uses 0.40 wt % Fe2O3 and 3.0% manganese oxide (8.46:1 molar         ratio of Mn to Fe)                                                             5) Melt D5 uses 0.60 wt % Fe2O3 and 3.0% manganese oxide (5.57:1 molar         ratio of Mn to Fe)                                                             6) Melt D6 uses 0.80 wt % Fe2O3 and 3.0% manganese oxide (4.23:1 molar         ratio of Mn to Fe)                                                       

The glass composition of Example 1 (DBD-1) and Example 2 (D1 through D6) were tested and found to reduce the transmission of ultraviolet light and in addition, possess melting and forming properties similar to commercially feasible soda-lime glass.

U.V. glass analyses for melts D1 through D6 (Example 2) are as follows:

U.V. Glass DOE Analysis For `D` Series Melts

The measured values for dominant wavelength, brightness, and purity for the D series glass melts were analyzed with an ANOVA Program to determine any significant effect, the percent contribution and test validity. The following table summarizes the results from these tests:

Details of the U.V. absorption form melts D1, D2, D3, D4, D5, and D6 are as follows:

    ______________________________________                                                 Dominant       %        %                                              Melt    Wavelength     Brightness                                                                              Purity                                         ______________________________________                                         D1      580.1          20.47    75.2                                           D3      565.9          16.6     70.8                                           D4      639.0           0.02    100.0                                          D6      572.7          11.45    85.9                                           ______________________________________                                    

Extra melts:

    ______________________________________                                         D2      569.8          24.73  67.5                                             D5      577.7          15.19  87.2                                             ______________________________________                                    

The attached three sheets show the ANOVA results. The conclusions are:

    ______________________________________                                         1.    Dominant wavelength:                                                           Significant constituents:  Mn 12%  Fe 28%                                      Error 60% = marginal test (0-60% good, 60-80% marginal,                        >80% poor)                                                               2.    Brightness:                                                                    Significant constituents:  Mn 51%                                              Insignificant                                                                  Error 60% = marginal test (0-60% good, 60-80% marginal,                        >80% poor)                                                               3.    Purity:                                                                        Significant constituents:  Mn 74%  Fe 12%                                      Error 14% = good test                                                    ______________________________________                                    

    ______________________________________                                         ANOVA Table - Raw Data (D1 thru D6 Series)                                     Source                                                                               Pool    Df    S     V     F      S'    rho %                             ______________________________________                                         MNO   [N]     1     398.003                                                                              398.003                                                                              16.920 374.480                                                                              73.85                             FE    [N]     1     85.562                                                                               85.562                                                                               3.637  62.040                                                                               12.23                             ERR   [Y]     1     23.523                                                                               23.523                                               e1    [N]     0     0.000                                                      e2    [N]     0     0.000                                                      (e)           1     23.523                                                                               23.523       70.568                                                                               13.92                             Total         3     507.087                                                                              169.029                                              ______________________________________                                    

    ______________________________________                                         ANOVA Table - Raw Data (D1 thru D6)                                            Source                                                                               Pool    Df    S     V     F      S'    rho %                             ______________________________________                                         MN    [N]     1     157.001                                                                              157.001                                                                              4.184  119.478                                                                              51.49F                            E     [Y]     1     12.320                                                                               12.320                                               ERR   [Y]     1     62.726                                                                               62.726                                               e1    [N]     0     0.000                                                      e2    [N]     0     0.000                                                      (e)           2     75.046                                                                               37.523       112.570                                                                              48.51                             Total         3     232.047                                                                              77.349                                               ______________________________________                                    

    ______________________________________                                         ANOVA Table - Raw Data (D1 thru D6)                                            Source                                                                               Pool   Df    S      V      F    S'     rho %                             ______________________________________                                         MN    [N]    1     1079.123                                                                              1079.123                                                                              1.590                                                                               400.519                                                                               1186                              FE    [N]    1     1620.060                                                                              1620.060                                                                              2.387                                                                               941.457                                                                               27.87                             ERR   [Y]    1     678.603                                                                               678.603                                              e1    [N]    0     0.000                                                       e2    [N]    0     0.000                                                       (e)          1     678.603                                                                               678.603     2035.810                                                                              60.27                             Total        3     3377.786                                                                              1125.929                                             ______________________________________                                    

The useful Mn to Fe ratio is one that minimizes color and maximizes U.V. absorption. For example, D-1 (Mn/Fe=5.64/1) has a hint of yellow or amber. A small amount of cobalt could be used resulting in a slight green color. D-2 has slightly better U.V. protection and has a faint or slight green-yellow color (Mn/Fe=3.71/1). D-3 (Mn/Fe=2.82/1) has slightly better U.V. protection than does D-2 and is slightly green. D-4 is faintly purple (excess Mn⁺³) and a ratio=8.46/1. D-5 approximates D-3 in U.V. protection, ratios=5.57/1. D-6 has poor U.V. protection, and has a slightly darker green-yellow tint ratio=4.23/1.

The Mn/Fe ratio generally can be from about 2.8/1 to about 6.5/1. The best results generally are about 5.2/1 to 5.8/1 for the Mn/Fe ratio.

Manganese oxide is added to oxidize the iron to the +3 state which is the UV absorbing ingredient. Mn⁺³ is a purple color in glass but becomes colorless in the +2 state as the iron is oxidized. 

What we claim is:
 1. A soda-lime-silica container glass composition consisting essentially of the following ingredients in weight percents;

    ______________________________________                                         Ingredients    Weight                                                          ______________________________________                                         SiO.sub.2      69-74                                                           Na.sub.2 O     11-15                                                           CaO             9-13                                                           MgO            0.005-3.0                                                       MgO            0.005-3.0                                                       K.sub.2 O      0.005-1.0                                                       SO.sub.3       0.1-0.5                                                         Fe.sub.2 O.sub.3 + FeO                                                                        0.3-1.0                                                         MnO + MnO.sub.2                                                                                2.2-2.8.                                                       ______________________________________                                    


2. A composition as defined in claim 1 in which in the UV absorption is from 290 to 390 nm.
 3. A composition as defined in claim 1 in which the MnO+MnO₂ is about 2.6 wt. percent.
 4. A composition as defined in claim 1 in which the amount of MnO+MnO₂ is about 2.4 to 2.6 wt. percent.
 5. A composition as defined in claim 1 in which FeO+Fe₂ O₃ is about 0.6 wt. percent and MnO+MnO₂ is about 2 to 3 wt. percent.
 6. A glass container made of the glass composition of claim
 1. 7. A clear soda-lime silica flint glass container made from a glass composition that absorbs UV light and consists essentially of the following ingredients in approximate weight percents:

    ______________________________________                                         Ingredients    Weight                                                          ______________________________________                                         SiO.sub.2      69-74                                                           Na.sub.2 O     11-15                                                           CaO             9-13                                                           MgO            0.5-2                                                           K.sub.2 O      0.1-0.5                                                         SO.sub.3       0.1-0.5                                                         Fe.sub.2 O.sub.3 + FeO                                                                        0.4-0.8                                                         MnO + MnO.sub.2                                                                                2.0-3.0.                                                       ______________________________________                                    


8. A clear transparent soda-lime-silica flint glass container made from a glass composition consisting essentially of the following ingredients in weight percents;

    ______________________________________                                         Ingredients    Weight                                                          ______________________________________                                         SiO.sub.2      69-74                                                           Na.sub.2 O     11-15                                                           CaO             9-13                                                           MgO            0.005-3.0                                                       K.sub.2 O      0.005-1.0                                                       SO.sub.3       0.1-0.5                                                         Fe.sub.2 O.sub.3 + FeO                                                                        0.3-1.0                                                         MnO + MnO.sub.2                                                                                2.0-3.1                                                        ______________________________________                                    

to thereby provide a clear transparent container that absorbs UV light to prevent damage to its contents.
 9. A container as defined in claim 8 in which at least about 80 wt % of the total iron content is in the ferric state.
 10. A container as defined in claim 8 in which the amount of MnO+MnO₂ is about 2.2 to 2.8 wt. percent.
 11. A container as defined in claim 8 in which the amount of MnO+MnO₂ is about 2.4 to 2.6 wt. percent.
 12. A container as defined in claim 8 in which the total initial iron content is expressed as Fe₂ O₃ and FeO and the wt. ratio of Fe²⁺ /Fe³⁺ is about 0.3/1 to 0.1/1.
 13. A container as defined in claim 8 in which FeO+Fe₂ O₃ is about 0.6 wt. percent and the amount of MnO+MnO₂ is about 2 to 3 wt. percent.
 14. A container is defined in claim 8 in which the UV absorption is from about 290 to 390 nm.
 15. A composition as defined in claim 1 in which the Fe₂ O₃ is present as at least about 80% wt. of the Fe₂ O₃ and FeO ingredient.
 16. A composition as defined in claim 1 in which the iron content is expressed as Fe₂ O₃ and FeO and the wt. ratio of Fe²⁺ /Fe³⁺ is about 0.3/1 to 0.1/1. 